OVERVIEW

Dropped by other malware, Downloaded from the Internet, Propagates via removable drives

This worm arrives via removable drives. It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It uses the default Windows folder icon to trick users into opening the file. Double-clicking the file executes this malware.

It sends gathered information to a predetermined email address using its own Simple Mail Transfer Protocol (SMTP) engine.

TECHNICAL DETAILS

File Size:

1,615,360 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

03 Oct 2012

Arrival Details

This worm arrives via removable drives.

It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Installation

This worm drops the following copies of itself into the affected system:

%User Profile%\gupd.exe

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)

It uses the default Windows folder icon to trick users into opening the file. Double-clicking the file executes this malware.

Autostart Technique

This worm adds the following registry entries to enable its automatic execution at every system startup:

It adds the following registry keys as part of its installation routine:

HKEY_CURRENT_USER\Software\Chilkat Software, Inc.

HKEY_CURRENT_USER\Software\Chilkat Software, Inc.\ChilkatMail

HKEY_LOCAL_MACHINE\SOFTWARE\Chilkat Software, Inc.

HKEY_LOCAL_MACHINE\SOFTWARE\Chilkat Software, Inc.\ChilkatMail

Propagation

This worm drops the following copy(ies) of itself in all removable drives:

essay.exe

lecture notes.exe

portfolio.exe

Stolen Information

This worm sends gathered information to a predetermined email address using its own Simple Mail Transfer Protocol (SMTP) engine.

Other Details

This worm connects to the following URL(s) to check for an Internet connection:

http://www.google.com/index.html

NOTES:

Upon execution, it checks for its existence by querying the value of HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run\gtalkupdate.

SOLUTION

Minimum Scan Engine:

9.200

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

Identify and terminate files detected as WORM_SILLY.SS

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Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.

If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.

If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

To terminate the malware/grayware/spyware process:

Scan your computer with your Trend Micro product and take note of the name of the malware/grayware/spyware detected.

In the list of running programs, locate a malware/grayware/spyware file detected earlier.

Select the detected files, then press either the End Task or the End Process button, depending on the version of Windows you are using.

Do the same for the remaining detected malware/grayware/spyware files in the list of running programs.

To check if the malware/grayware/spyware process has been terminated, close Task Manager, and then open it again.

Close Task Manager.

Step 3

Delete this registry key

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Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry. Before you could do this, you must restart in Safe Mode. For instructions on how to do this, you may refer to this page If the preceding step requires you to restart in safe mode, you may proceed to edit the system registry.

In HKEY_CURRENT_USER\Software

Chilkat Software, Inc.

In HKEY_LOCAL_MACHINE\SOFTWARE

Chilkat Software, Inc.

To delete the registry key this malware/grayware/spyware created:

Restart your computer in Safe Mode. For instructions on how to do this, you may refer to this page. If the preceding step requires you to restart in safe mode, you may proceed to #2.

Open Registry Editor. To do this, click Start>Run, type REGEDIT in the text box provided, then press Enter.

In the left panel of the Registry Editor window, double-click the following: HKEY_CURRENT_USER>Software

Still in the left panel, locate and delete the key:Chilkat Software, Inc.

In the left panel of the Registry Editor window, double-click the following: HKEY_LOCAL_MACHINE>SOFTWARE

Still in the left panel, locate and delete the key:Chilkat Software, Inc.

Close Registry Editor.

Step 4

Delete this registry value

[ Learn More ]

[ back ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run

gtalkupdate = "%User Profile%\gupd.exe"

To delete the registry value this malware created:

Open Registry Editor. To do this, click Start>Run, type regedit in the text box provided, then press Enter.

In the left panel of the Registry Editor window, double-click the following: HKEY_CURRENT_USER>Software>Microsoft>Windows>CurrentVersion>Run

In the right panel, locate and delete the entry:gtalkupdate = "%User Profile%\gupd.exe"

Close Registry Editor.

Step 5

Scan your computer with your Trend Micro product to delete files detected as WORM_SILLY.SS. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.